Haemopoietic stem cells: spleen colony-forming cells are normally actively proliferating.
The haemopoietic stem cells forming spleen colonies (CFU-S) had on average 30 to 40% of cells engaged in the DNA synthesis in normal mice continuously over 4 years. A majority of experiments aimed at the suppression of the CFU-S proliferation, which included suppression of the T-lymphocytes by means of cyclosporin A or by adult thymectomy, administration of antibacterial and antifungal agents and maintainance of mice in a sterile environment, suppression of antibody-producing cells by a successive administration of the bacterial lipopolysaccharide and cyclophosphamide and attempts to increase the total number of CFU-S in the body through massive transfusions of bone marrow cells or by grafting plugs of the bone marrow under the kidney capsulae, have not been sufficiently effective. A transient suppression of CFU-S proliferation occurred during recovery of the haemopoietic tissue from damage caused by cyclophosphamide. The results support the view that changes in CFU-S numbers and in the proportion of them in DNA synthesis may be positively correlated when CFU-S numbers fluctuate physiologically about their normal values. The failure to manipulate the CFU-S proliferation rate easily suggests that proliferation of these cells may not be under a strong 'switch on - switch off' control.
Necas
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E
Department of Pathophysiology, 1st Faculty of Medicine, Charles University, Prague, Czechoslovakia.
Znojil
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V
Sefc
L
L
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000921:Antibody-Producing Cells / Q000187:drug effects; D016026:Bone Marrow Transplantation; D002455:Cell Division / Q000187:drug effects; D003520:Cyclophosphamide / Q000494:pharmacology; D003524:Cyclosporins / Q000494:pharmacology; D005260:Female; D005856:Germ-Free Life; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D007165:Immunosuppression Therapy; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D011112:Polymyxin B / Q000494:pharmacology; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000187:drug effects; D013934:Thymectomy
D000900:Anti-Bacterial Agents; D003524:Cyclosporins; D003520:Cyclophosphamide; D011112:Polymyxin B